Population dynamics and trophic interactions in arctic birds and mammals

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The long-term goals of my research program are to (1) understand the effects of human-induced changes in climate and habitat on the population dynamic and trophic interactions of arctic birds and mammals and (2) develop and validate innovative quantitative methods to study animal populations. My research is centered on long-term population studies of two herbivorous groups of the tundra, the migratory snow geese and the resident lemmings, and of their predators on Bylot Island, NU. I will evaluate if the directional selection for an early breeding date increased in snow geese over a 25-year period in response to a temporal mismatch between geese and their food plant induced by climate warming. Support for this hypothesis would indicate that arctic birds are failing to adjust to warming temperature, and are thus threatened. I will also examine the sensitivity of wing moult to environmental conditions in geese and determine if the timing of moult and the quality of new feathers may be impaired by warming temperature. Another objective is to build demographic models linking temperature to population size in order to predict population changes under various climatic scenarios. Finally, I will test predictions from two alternative hypotheses on the causes of lemming population cycles, the winter food limitation and the predation hypotheses. Experiments will determine if lemming population crashes are due to overgrazing of their food in winter or to the high consumption rate of predators during the summer. My projects will provide training for several BSc, MSc and PhD students in biology. By combining unique, long-term datasets with innovative analytical tools, my research program offers a unique opportunity to increase our understanding of the functioning of food webs and improve our ability to make quantitative predictions on the future of animal populations. This work will also contribute to the management and conservation of several arctic wildlife species and of their habitat.